Would a, relatively, soft/bendable spear pierce an aspis? I agree it would be interesting, regardless, especially since Romans pretty much copied the hoplite tactics and perfected them.
Nonsense. Read your history before you make grand claims like these. The Spartans never sought to rule the whole of Greece, eventhough they beat Athens and their allies on more then one occassion. As for your rubbish 'ranged pwns them' argument, have you ever seen an aspis? No arrow gets passed that.
You have a point with the vision thing, but the Spartan would have had major training with the shield, and I still can't see a samurai getting past it too fast for a Spartan to turn and block it, but that would greately depend on the skill of the fighters involved. Also, a Spartan's main weapon would be his spear, not the daggerlike weapon. I also seem to recall that they used larger swords in addition to the daggerlike ones, not sure if it was standard issue though. Also, shield + short range weapon beats longer twohanded weapons, because the closer you get, the less useful a longer weapon becomes.
I don't know what you mean with a yari as I know little of Japanese weaponry, but I don't see anything short of a 2handed axe or something destroying an aspis. Also, the last bit I quoted made no sense to me at all, are you saying swords could be used as blunt weapons to pierce armour?!
In the end, it all comes down to the individual warrior. Who makes the first mistake, who is more skilled, who is having a bad day...